I just equiped a helmet and did the Dragon Aspect shout, turned camera to third person, I saw no beard, thought it had something to do with the lightening of Dragon Aspect, after the battle was over, I took off my helmet and the beard was still gone, I so hate how my Nord looks like that, tried to put it on and take it off again, and nothing, any ideas?

Well that's just plain bizarre.
Sorry to hear that happened.

Two ideas:
- Load a previous Save and check
- Head to the Ragged Flagon in Riften's Ratway and see if Galathil can help

Had to load a save about 1hr before the damn problem happened, I must say it's too damn boring to do all that black book quest again as it gets me nervous, but this time the problem didn't occur, I just hope it doesn't happen again.

This happened to me also, but it suddenly reappeared after 5 minutes or so. To me it was when i entered apocrypha, with the dragon aspect equipped (all words) my character was a male nord..